Coater head

ABSTRACT

The specification discloses a coater head for depositing coating sidewalls on webs such as paper webs. The disclosed coater head comprises a pressure container beneath the web and having a nozzle on the top extending upwardly from the container and diverging toward the web in the direction in which the web travels. The nozzle has end walls extending between the diverging sidewalls and at least one slide is mounted in the nozzle and is movable transversely of the web to vary the effective opening of the nozzle. The slide has an end wall parallel to the nozzle end wall and has at least one blade engaging one of the sidewalls of the nozzle. The nozzle wall engaged by the blade is cut off or has openings therein which are uncovered when the slide moves inwardly of the nozzle so that the coating flows from the container along the full length of the nozzle but only rises to the web over the width thereof determined by the slide adjustment. Obstruction to the flow of coating material is thereby eliminated and the formation of deposits in the container or nozzle due to obstruction of flow is eliminated.

United States Patent [72] inventors Franz Krautzberger;

Josef Geistbeck, both of Heidenheim,

- Germany [21 Appl. No. 7,597 [22] Filed Feb. 2, 1970 [45] Patented Aug. 17, 1971 [73] Assignee J. M. Voith Gmbll Heidenheim, Germany [32] Priority Feb. 19, 1969 [33] Germany [31] P19 08 163.1

[54] COATER HEAD 6 Claims, 3 Drawing Figs.

3,285,225 11/1966 Recor 118/410 Primary Examiner-Henry S. J audon Att0meyMelvin A. Crosby ABSTRACT: The specification discloses a coater head for depositing coating sidewalls on webs such as paper webs. The disclosed coater head comprises a pressure container beneath the web and having a nozzle on the top extending upwardly from the container and diverging toward the web in the direction in which the web travels. The nozzle has end walls extending between the diverging sidewalls and at least one slide is mounted in the nozzle and is movable transversely of the web to vary the effective opening of the nozzle. The slide has an end wall parallel to the nozzle end wall and has at least one blade engaging one of the sidewalls of the nozzle. The nozzle wall engaged by the blade is cut off or has openings therein which are uncovered when the slide moves inwardly of the nozzle so that the coating flows from the container along the full length of the nozzle but only rises to the web over the width thereof determined by the slide adjustment. Obstruction to the flow of coating material is thereby eliminated and the formation of deposits in the container or nozzle due to obstruction of flow is eliminated.

PATENTEUAUGITIQTI $599,602

INVENTOR. FRANZ KRlUTZBfiRGE R BY JOSE? GEISTBECK MAM Q ER HE D The present invention relates to a coating head for the application of coating materials to moving webs, such as paper webs. More particularly still, the present invention relates to a coating head for deposit ng coating materials on moving webs in which the width of the applied coating, measured transversely of the web, can be adjusted.

Coating heads of the nature referred to are known in the art and may comprise, for example, a pressure container located beneath the web to be coated and extending the transverse direction of the web. The container is supplied with the coating material and carries a nozzle on the top which is presented to the web and .into which no ule the coating material flows so that it comes into contact with the web to be coated. Such a nozzle has two sidewalls, or lips, extending transversely of the Web and spaced in the direction of movement of the web and two end walls connecting the lips at the ends thereof and extending in the direction of movement of the web.

A coating head of this general type is described in the Paper I Trade Journal .of r. l3, 1967, under the heading COATER HEAD" and shows an arrangement whereby the width of the applied coating can be adjusted. In this arrangement, at each end of the nozzle, there is located a laterally movable slide member which can be shifted in the transverse direction of the web and which bridges over the aforementioned lips of the nozzle to reduce the effective width thereof which is exposed to the web.

with this arrangement, the portions of the nozzle outlet at a the sides are blocked off and the coating material emerges from the noule along the length thereof which is exposed betweenthe inner edges of the aforementioned slide members. The coater head described above is adequate for adjusting the width of the region of Web which is coated but introduces certain problems that cause difficulties in connection with the deposition of the coating material on the web. In particular, when the ilow of the coating material is obstructed the material tends to form deposits and lumps at the obstruction which can be dislodged and deposited on the region of the web being coated, and suchdeposits can interfere with the free movement of the coating material.. Such lumps form more readily when the flow path of the coating material changes direction at an acute angle and when dead corners and dead" ends ,are enco ntered by the coating material. In short,

anything that interferes with the uniform laminar flow of the coating material introduces the possibility of the formation of lumps therein.

In thevadjustable coating head of the prior art referred to above, equipped with the slide members, there is formed a blocked-off region at each end of the nozzle when the slide members arepushed, in and this interferes with the streaming of the coating material through the nozzle and causes a sharp change indirection thereof and, because of this, coating heads of this nature are subject to, the formation of deposits and lumps therein. v Withthe foregoing in mind, it is a primary objective of the present invention to provide a coating head for the application of coating material to moving webs which is'adjustable as to the width of the applied coatingbut which entirely eliminates theproblems referred to above that have been encountered with prior art coating heads.

A further object of the present invention is the provision of a coatcr head of the nature referred. to in which the flow of coating materialthrough the coating head and the nozzle portion thereof is always in the form of substantially laminar flow.

Still another object is the provision of a coater head of the nature referred to which is readily adjustable as to the width of the coating applied to a web and. wherein all obstructions to flow of the coating materialare prevented while the width of the applied coatingcanbe accurately controlled.

SUMMARY OF THE INVENTION The present invention provides a coating head in which a nozzle extending upwardly from a pressure container is presented to the region of a web to be coated. The coating material is supplied to the container under pressure and rises in the nozzle to the web and coats the web while excess coating material overflows the nozzle and drops into a catch basin beneath the nozzle and container.

The container and nozzle extend transversely beneath the web and the nozzle has lips extending perpendicular to the direction of travel of the web and spaced in the direction of travel of the web and also has end walls extending between the lips and closing the nozzle at the ends. At least one end of at least one lip is provided with a cutout portion through which coating material entering the nozzle from the container can flow when the cutout is uncovered. The cutout portion may be a notch in the lip or a complete section of the lip may be cut off, or the cutout portion may be in the form of one or more apertures in the lip.

The nozzle carries a coating width adjusting slide having a blade portion lying along the cutout lip and a transverse wall parallel to the end wall of the nozzle. The slide, in an outer position, provides for maximum width of coating and has its transverse wall against the nozzle end wall and its blade portion covering the aforementioned cutout. For narrower coating widths, the slide is moved inwardly and the transverse wall thereof becomes spaced from the nozzle end wall and the blade portion uncovers at least a portion of the cutout. The lateral wall of the slide now determines the lateral edge of the coated region of the web while coating material flowing from the container in the region of the nozzle disposed outwardly from the lateral wall of the slide discharges via the cutout to the catch basin and does not rise to the level of the web.

The lateral wall may be provided with a slidelike member connected thereto and extending outwardly from the lateral wall beneath the level of the web and above the level of the container and forming a shield to prevent coating material rising from the container outside the lateral wall from reaching the web.

The flowing of the coating material from the container upwardly is unobstructed across the entire length of the container and there is no region along the length of the container that the flow of the coating material will be held up or obstructed or delayed so that deposits will not be built up and no lumps of material .will be formed which can break off and flow with the coating material to the web surface.

The cutout referred to may be in one or both lips of the noz- -zle and may be provided at one or both ends of the nozzle. The

cutout, or cutouts, extend to the extreme end of the nozzle and inwardly along the nozzle to the desired minimum coating widths. In this manner, as soon as a slide is moved inwardly of the nozzle to reduce the coating width, at least a portion of the cutout region of the nozzle is uncovered to permit coating material to spill over therefrom to the catch basin rather than being obstructed within the container or nozzle which, as mentioned above, can lead to undesirable deposits that could interfere with the quality of the coating applied to the web.

A feature of the present invention is to be found in the formation of the container and the nozzle so that in transverse cross section the container walls merge smoothly with the nozzle for creating smooth flow of the coating material. Further, the nozzle lips or sidewalls diverge toward the web to be coated and the trailing or downstream one of the lips is preferably disposed at an acute angle to the adjacent surface of the web and may also be adjustable to vary the angle at which it is presented to the web.

The coating material in flowing through the cutout, or cutouts, follows such a path that sufficient head is maintained on the coating material within the effective range of the nozzle to insure that the coating material will rise in the nozzle to the level of the web being coated. The jetlike action that is imparted to the coating material when it flows through the slot in the top of the container into the nozzle further assists in causing the coating material to rise to the top of the nozzle and engage the web to be coated.

The coating material overflowing the nozzle, and overflowing at the cutouts, back into the catch basin may be pumped directly back into the container or it may be returned to a processing point for adjustment of the characteristics thereof and then returned to the container.

The aforementioned slide or slides associated with the nozzle can be adjusted in any of several manners such as by a threaded spindle connected to the slide and threaded through a stationary'nut and with one of the nut and spindle driven by a worm drive.

The entire coating head, including the catch basin, may be adjustably mounted for tilting movement toward and away from the web being coated and to vary the distance of the lips from the web being coated.

By widening the nozzle in a direction toward the web, a stopping of the movement of the coating material at the web, and which could lead to undesirable depositions, is avoided. Rather, the diverging lips can even bring about a reversal of a flow of the material adjacent the web leading to a certain turbulent condition in the material, especially adjacent the lips of the nozzle, which will prevent particles of the coating material from being precipitated and building up as deposits.

The foregoing objects as well as still other objects and advantages of the present invention will be more clearly understood upon reference to the following specification, taken in connection with the accompanying drawings, in which:

'FIG. I is a schematic side view showing a coating installation including a coating head according to the present inventron;

FIG. 2 is a fragmentary perspective view showing one form which the coating head can take; and

FIG. 3 is a fragmentary perspective view showing another form which the coating head can take.

DETAILED DESCRIPTION OF THE INVENTION In the drawings, FIG. I shows a pressure containerv which has a connection nipple 2, a nozzle arrangement 3, and a dischargevalve 4. Nozzle 3 is presented to the downwardly facing side of a web 6, a paper web, for example, entrained about the bottom of a support or guide roll 5. Sheet metal guide members 7 are installed on opposite sides of container 1 and lead downwardly into a catch basin 8 having a discharge conduit 9. The complete coating head is pivotal about a pivot axis 30 under the action of a fluid motor 32 and is, furthermore, tiltable by a pivot 33 by a fluid motor 34. The fluid motors, as referred to, and the tiltability of the coating head insures that the nozzle 3 will be presented properly to the web being coated and at the proper angle thereto.

It will be noted that the web 6 moves in the direction of the arrow and that the trailing or downstream lip 3a of the nozzle 3 is inclined at an acute angle thereto. This lip may, furthermore, be angularly adjustable on nozzle 3 to change the angle at which it is presented to the web.

FIG. 2 shows one manner in which a coating width adjusting slide could be provided for a coating head of the nature illustrated in FIG. I. In FIG. 2, the pressure container is indicated at 10 and is provided in the top with a slot 11 opening into a nozzle having the two sidewalls or lips 12 connected to container 10 on opposite sides of slot 11 and upstanding from the container. Lips 12 are interconnected at the ends thereof by end walls 13, only one of which is shown in FIG. 2. The container l0 and the nozzle extending upwardly therefrom, similarly to the container 1 and nozzle 3 in FIG. I, extend in the transverse direction of the web to be coated.

The nozzle in FIG. 2 engages the downwardly facing side of a web, such as a paper web, one side of which is indicated with a dot-dash line at 14. This web may move, for example, in the direction of arrow 15 in FIG. 2.

As will be seen in FIG. 2, the lips 12 of the nozzle extending v upwardly from container 10 are provided with cutouts 16 at the ends. Furthermore, a slide 17 is mounted in the nozzle and has the longitudinally extending blade portions 19 engaging the insides of lips 12 and a lateral wall 18 extending between and connecting the two blade portions 19 at the one end thereof.

In an outermost position, wall 18 engages the inside of nozzle end wall 13 and blade portions 19 just cover the cutouts 16. This adjustment of slide 17 provides for maximum coating width. Reduced width coating is provided for by moving slide 17 inwardly of the nozzle up to the point that end wall l8"is about at the ends of the cutouts 16. When slide 17 is adjusted inwardly, the coating material supplied through slot 11 in the region between lateral wall 18 and nozzle end wall 13, spills over from cutouts 16 as indicated by curved arrows 16a and, thus, does not rise to the level of the web. Under these circumstances, the lateral wall 18 of the slide determines the width'of the applied coating.

In FIG. 3, an arrangement is shown which is similar to that of FIG. 2. In FIG. 3, the pressure container has lips 20 and 21 upstanding therefrom to form a nozzle. One end wall 13 is shown at the end of lip 20. Lip 21 is completely out out at the one end of the nozzle and the slide 17 has a blade portion 26 extending the full height of lip 21 and adapted for variably closing off the cutout formed by the cutoff portion of lip 21. The slide 17, as before, has a lateral wall 18 and may, furthermore, have a second blade portion 27 which, although not functional, adds strength to the slide structure.

In FIG. 3, there is attached to lateral wall 18 of slide 17 a deflecting sheet or wall25. This wall extends horizontally outwardly from lateral wall 18 on the opposite side thereof from the blade portions and covers the portion of the nozzle between lateral wall 18 and the nozzle end wall 13, and deflects the coating material rising from slot 11 in that region downwardly into the catch basin beneath the container. Member 25 is disposed at a level below that of the web and above the top of the container and not only prevents the coating material outwardly from lateral wall 18 from engaging the web but also insures that the proper pressure will be maintained on the coating material within the container so that the material supplied to the effective portions of the nozzle will rise to the level of the web and effect proper coating of the web. a

The web has been shown as entrained about a support roller but can be arranged to slide over a stationary surface, if so desired.

Modifications may be made within the scope of the appended claims.

What we claim is:

l. A coating head for applying flowable coating material to a moving web, such as a paper web, over a range adjustable between maximum and minimum coating widths, said web presenting the surface to be coated downwardly; a pressure container beneath the surface extending in the cross direction of the web, nozzle means extending upwardly from said container toward said surface and having a pair of lip means spaced in machine direction from each other and extending in cross direction of the web, and end wall means extending between said lip means, slot means in the top of said container for supplying coating material to said nozzle means for flow upwardly therein to said web, at least one of said lip means having at least one cutout therein in the region thereof which lies between the respective lateral extremities of said 'maximum and minimum coating widths, and slide means carried by said nozzle means and being adjustable thereon in the cross direction of the web for varying the coating width of said head, said slide means comprising a blade portion engaging said one lip means and also comprising a lateral wall attached to the blade portion and parallel to said end wall means, said slide means having an extreme outer position on said nozzle means wherein said lateral wall engages said end wall means and said blade portion covers said cutout for maximum coating width,

upwardly opening catch basin beneath said pressure container into which coating material overflowing from said nozzle means and discharging via said cutout drains.

3. A coating head according to claim 2, in which said lip means diverge in the direction from said container toward said surface.

4. A coating head according to claim 2, in which the lip means at the trailing side of said nozzle means is inclined at an acute angle to the said surface adjacent thereto.

5. A coating head according to claim 2, in which the contour of said container and nozzle means when viewed in cross section merge smoothly with each other and thereby present the minimum obstruction to flow of the coating material therethrough.

6. A coating head according to claim 2, which includes a horizontal wall element attached to said lateral wall of said slide means and movable with said slide means, said horizontal wall extending outwardly from said lateral wall and being disposed at a level between that of said web and that of said slot in said container and being operable to shield said web from the coating material flowing from said container in the region outwardly of said lateral wall of said slide means. 

1. A coating head for applying flowable coating material to a moving web, such as a paper web, over a range adjustable between maximum and minimum coating widths, said web presenting the surface to be coated downwardly; a pressure container beneath the surface extending in the cross direction of the web, nozzle means extending upwardly from said container toward said surface and having a pair of lip means spaced in machine direction from each other and extending in cross direction of the web, and end wall means extending between said lip means, slot means in the top of said container for supplying coating material to said nozzle means for flow upwardly therein to said web, at least one of said lip means having at least one cutout therein in the region thereof which lies between the respective lateral extremities of said maximum and minimum coating widths, and slide means carried by said nozzle means and being adjustable thereon in the cross direction of the web for varying the coating width of said head, said slide means comprising a blade portion engaging said one lip means and also comprising a lateral wall attached to the blade portion and parallel to said end wall means, said slide means having an extreme outer position on said nozzle means wherein said lateral wall engages said end wall means and said blade portion covers said cutout for maximum coating width, and said slide means being adjustable inwardly on said nozzle means to reduced coating width positions wherein said lateral wall is spaced inwardly along said nozzle means from said end wall means and said blade portion at least partly uncovers said cutout.
 2. A coating head according to claim 1, which includes an upwardly opening catch basin beneath said pressure container into which coating material overflowing from said nozzle means and discharging via said cutout drains.
 3. A coating head according to claim 2, in which said lip means diverge in the direction from said container toward said surface.
 4. A coating head according to claim 2, in which the lip means at the trailing side of said nozzle means is inclined at an acute angle to the said surface adjacent thereto.
 5. A coating head according to claim 2, in which the contour of said container and nozzle means when viewed in cross section merge smoothly with each other and thereby present the minimum obstruction to flow of the coating material therethrough.
 6. A coating head according to claim 2, which includes a horizontal wall element attached to said lateral wall of said slide means and movable with said slide means, said horizontal wall extending outwardly from said lateral wall and being disposed at a level between that of said web and that of said slot in said container and being operable to shield said web from the coating material flowing from said container in the region outwardly of said lateral wall of said slide means. 